Meat Yield and Quality of Tanzania Shorthorn Zebu Cattle Finished On
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Journal of Agriculture and Rural Development in the Tropics and Subtropics Vol. 117 No. 1 (2016) 125–135 urn:nbn:de:hebis:34-2016030349953 ISSN: 2363-6033 (online); 1612-9830 (print) – website: www.jarts.info Meat yield and quality of Tanzania Shorthorn Zebu cattle finished on molasses/maize grain with agro-processing by-products in 90 days feedlot period Lovince Asimwe a,∗, Abiliza Kimambo a, Germana Laswai a, Louis Mtenga a, Martin Weisbjerg b, Jorgen Madsen c, John Safari d aDepartment of Animal Science and Production, Sokoine University of Agriculture, Morogoro, Tanzania bDepartment of Animal Science, AU Foulum, Aarhus University, Tjele, Denmark cDepartment of Larger Animal Sciences, University of Copenhagen, Frederiksberg, Denmark dInstitute of Rural Development Planning, Dodoma, Tanzania Abstract This study was conducted to evaluate the effects of feeding molasses or maize grain with agro-processing by-products on yield and quality of meat from Tanzania shorthorn zebu (TSZ) cattle. Forty five steers aged 2.5 to 3.0 years with 200 ± 5.4 kg body weight were allocated into five dietary treatments namely hominy feed with molasses (HFMO), rice polishing with molasses (RPMO), hominy feed with maize meal (HFMM), rice polishing with maize meal (RPMM) and maize meal with molasses (MMMO). Ad libitum amount of each dietary treatment and hay were offered to nine steers for 90 days. Cooking loss (CL) and Warner Bratzler shear force (WBSF) values were determined on M. longis- simus thoracis et lumborum aged for 3, 6, 9 and 12 days. Steers fed on HFMO diet had higher (P < 0.05) nutrient intake (86.39 MJ/d energy; 867 g/d CP), weight gain (919 g/d) and half carcass weight (75.8 kg) than those fed other diets. Meat of steers from all diets was tender with average WBSF values of 47.9 N cm −2. The CL (22.0 ± 0.61 %) and WBSF (53.4 ± 0.70 N cm−2) were highest in meat aged for 3 days followed by 6, 9 and 12 days. WBSF values for meat aged for 9 and 12 days from steers fed HFMO and RPMM diets were similar and lower than those on other dietary treatments × aging periods. Overall, molasses and hominy feed can be used to replace maize meal in feedlot finishing diets to spare its use in animal feeds. Keywords: agro-processing by-products, feedlot, retail cuts, steers 1 Introduction extrinsic factors (Mushi et al., 2009; Safari, 2010). In Tanzania, meat is mainly produced from Tanzania short- Meat quality is a complex parameter with varying horn zebu (TSZ) cattle which are extensively managed properties and is influenced by several intrinsic and ex- on range lands. In most of these range lands, pastures trinsic factors. The intrinsic factors include breed, sex, are in short supply with low nutritive values especially and slaughter weight, whereas pre- and post-slaughter during the dry seasons resulting in low animal growth carcass handling, type and feeding level are some of the rates, and late attainment of slaughter weights. Stud- ∗ ies have reported loss in weight leading to poor body Corresponding author ff ff Department of Animal Science and Production, Sokoine University condition which a ects meat yield (du Plessis & Ho - of Agriculture, P.O. Box 3004, Morogoro, Tanzania man, 2004) and quality (Muchenje et al., 2008). The Email: [email protected] Phone: +255 713 468 33 constraint of poor nutrition in beef production could Published online: April 26, 2016 Open access article licensed under a Creative Commons Attribution 4.0 International License CC BY http://creativecommons.org/licenses/by/4.0 126 L. Asimwe et al. / J. Agr. Rural Develop. Trop. Subtrop. 117 - 1 (2016) 125–135 be minimised by finishing animals in feedlot using di- assessed for health and nutritional status prior to the ex- ets based on agro-processing by-products. Rice polish- periment to minimise variation errors. Five concentrate ing and hominy feed are agro-processing by-products diets were formulated from different proportions of the that can substitute part of maize grain in concentrate raw materials of the agro-processing by products to con- feed for beef cattle (Matz, 1991). A study by Sani tain hominy feed with molasses (HFMO), rice polishing et al. (2014) on Bunaji bulls fed rice offal as energy with molasses (RPMO), hominy feed with maize meal source showed rice offal to yield high quality carcass (HFMM), rice polishing with maize meal (RPMM) and with lean meat (less amount of fat) compared to maize a control maize meal with molasses (MMMO). The pro- offal. Rice polishing and hominy feed have been found portions of the ingredients composition shown in Table to give consistent results when combined with molasses 1 were determined by trial and error method using nu- and urea (Lopez & Preston, 1977; Larson et al., 1993). tritive values of ingredients from feedstuff tables for ru- A study by Hunter (2012) on beef cattle found that in- minants developed by Doto et al. (2004). Each for- clusion of sugar cane molasses in feedlot diets has the mulated diet was fed together with hay ad libitum to 9 potential of producing meat with good eating quality. steers for a period of 90 days. All animals were provided Earlier study in Tanzania by Mwilawa (2012) on beef with free access of fresh drinking water throughout the fattening using maize meal and molasses has shown experiment and were housed in individual pens. Dur- that TSZ cattle responds well to fattening by increas- ing the experimental period, all animals were weighed ing carcass quantity from 90 kg for sole grazing group after every two weeks and the amount of feed eaten to 154 kg for maize meal and molasses fed group. was weighed daily. The amount of consumed com- Similarly, the quality of meat was improved from 60 pounded diet was 6.20 kg DM/day for MMMO, 6.91 kg Ncm−2 in the sole grazing group to 45 N cm−2 for DM/day for HFMO, 7.05 kg DM/day for RPMO, 5.29 maize meal and molasses fed group. However, the ma- kg DM/day for HFMM and 6.18 kg DM/day for RPMM jor limitation of using maize meal as cattle diet in Tan- diet while the consumed hay was 1.20 kg DM/day for zania is the role it plays as the main food source for MMMO, 1.15 kg DM/day for HFMO, 1.24 kg DM/day humans. Thus, it is of interest to find out alternat- for RPMO, 1.31 kg DM/day for HFMM and 1.32 kg ives to maize meal as feedlot diet which is less com- DM/day for RPMM diet. The metabolisable energy petitive to humans’ food. The available by-product (ME) content of hay was 4.8 MJ/kg DM while the crude feeds that could be used for finishing cattle under feed- protein (CP) content was 33 g/kg DM. The ME contents lot at national level were estimated to be (tones DM) of compounded feeds were estimated using the equation maize bran (5.6 × 105), rice-polishing (8.9 × 104), cot- by MAFF (1975), that was ME (MJ/kg DM) = 0.012 ton seedcake (6.2 × 104), wheat-bran (1.4 × 104), sun- CP + 0.031 EE + 0.005 CF + 0.014 NFE, whereas that flower seedcake (2.1 × 104), wheat-pollard (4.2 × 103) of hay was determined by the McDonald et al. (2002) and molasses (4.5 × 104) (Nandonde, 2008). We hy- equation: ME (MJ/kg DM) = 0.016 DOMD, where pothesize that molasses with other agro-processing by- DOMD = g digestible organic matter per kg dry mat- products can substitute maize meal in feedlot diets ter. without reducing meat yield and quality. Therefore, the objective of this study was to assess the yield and quality 2.2 Slaughter procedures of meat produced from TSZ cattle finished on molasses After 90 days of feeding, all animals were weighed or maize meal with agro-processing by-products under for three days consecutively to obtain the final body feedlot conditions. weight and transported by truck to Dodoma Abattoir (82 km from Kongwa ranch). At the abattoir, the animals 2 Materials and methods were deprived of feed for 24 hours, but had access to fresh drinking water. Slaughtering and dressing of the 2.1 Animals and diets animals followed the abattoir procedures as described A total of 45 TSZ steers aged 2.5–3.0 years with ini- by Bourguet et al. (2011). The animals were stunned us- tial body weight 200 ± 5.4 kg (mean ± SEM) were alloc- ing electrical stunner, slaughtered and suspended on an ated in a completely randomised design to feedlot exper- overhead rail system for bleeding, de-hiding and evis- iment performed at Kongwa ranch, located in Dodoma ceration. The head was removed at the atlanto-occipital region, central Tanzania. These animals were grazing joint, the forefeet and hind feet were removed at the on pastures available at the ranch area for back ground- carpal–metacarpal and tarsal–metatarsal joints, respect- ing before starting the experiment. Animals were also ively. The dressed carcasses were halved into two us- L. Asimwe et al. / J. Agr. Rural Develop. Trop. Subtrop. 117 - 1 (2016) 125–135 127 Table 1: Ingredient composition (kg/100 kg), Crude protein (g/kg DM) and Metabolisable energy (MJ/kg DM) levels of the dietary treatments Compounded diets Ingredients MMMO HFMO RPMO HFMM RPMM Ingredient composition (kg/100 kg as fed) Maize meal 38 – – 38 38 Hominy feed – 40 – 50 – Rice polishing – – 41 – 51 Molasses 47 47 47 – – Cotton seed cake 13 11 10 10 09 Mineral mix 1 1 1 1 1 Urea 0.5 0.5 0.5 0.5 0.5 Salt 0.5 0.5 0.5 0.5 0.5 Nutritive values Crude protein (g/kg DM) 122 120 97 145 111 Metabolisable energy (MJ/kg DM) 11.0 11.7 10.1 12.6 10.2 MMMO: maize meal with molasses; HFMO: hominy feed with molasses; RPMO: rice polishing with molasses; HFMM homing feed with maize meal; RPMM rice polishing with maize meal.